Solvation and hydrogenation of coal in partially hydrogenated hydrocarbon solvents

ABSTRACT

Coal is solubilized and hydrogenated in partially hydrogenated hydrocarbon streams such as clarified slurry oil to produce a nonviscous solution which is readily deashed by settling or filtering. Both inorganic sulfur and organically combined sulfur are removed, and the deashed solubilized coal thus produced has a very low sulfur content. The invention is also useful for producing a hydrogenated solubilized coal solution which is suitable for use as a feedstock for a petroleum refinery, and valuable liquid hydrocarbon distillate products boiling, for example, within the gasoline, kerosene, naphtha, light fuel oil and gas oil ranges may be produced therefrom.

United States Patent 3,188,179 6/1965 Gorin [72] Inventors William M.Leaders; 208/10 Jack W. Roach, both of Oklahoma City, 3,488,279 1/1970Schulman 208/10 Okl 3,514,394 5/l970 Wilson etal. 208/l PP;- 1,6899 1970Primary Examiner-Delbert E. Gantz [22] He d 1971 AssistantExaminer-Veronica O'Keefe [45] i p AtlameyShanley and ONeil [73]Asslgnee Kerr-McGee Corporation Oklahoma City, Okla.

[54] SOLVATION AND HYDROGENATION 0F COAL W L R ENATED HY ROCARBON 0G DABSTRACT: Coal is solubilized and hydrogenated in partially hydrogenatedhydrocarbon streams such as clarified slurry oil 30 Claims, 2 DrawingFigs.

to produce a l'lOllVlSCOUS solution WhlCh ls readily deashed by US.ttling or filtcring inorganic ulfur and organically com- 208/8 binedsulfur are removed, and the deashed solubilized coal [51] Int. Cl ClOg1/06 thus produced has a very low lf content. The invention is [50]Field of Search 208/ a|so f l f producing a hydrogenatedsolubilizedvcoal so|u 56 R f d tion which is suitable for use as afeedstock for a petroleum 1 e erences refinery, and valuable liquidhydrocarbon distillate products UNITED STATES PATENTS boiling, forexample, within the gasoline, kerosene, naphtha, 2,464,271 3/1949 Storchet al 208/l0 light fuel oil and gas oil ranges may be producedtherefrom.

45 46 44 sa slnoa V COAL MIXER H SOLUTIZER FlsrlER I f HEATER 24 28 8 l5l7 I6 I 25 26 2| 29 x l8 49$) SOLVENT 36 PATENTED SEP21 I971 3.601718sum 1 [IF 2 F l LTKfIR FIG. 1 A

:3 INVENTOR WILLIAM M. LEADERS JACK W. ROACH BY M'QW ATTORNEYS com.

SOLYENT SOLVATION AND HYDROGENATION OF COAL IN PARTIALLY HYDROGENATEDHYDROCARBON SOLVENTS BACKGROUND OF THE INVENTION The potentially solublesubstances in fossilized carbonaceous materials such as coal arecomposed largely of high molecular weight three-dimensional cyclicstructures which contain predominantly six membered rings. For example,coal contains bitumen and humin which have large flat aromatic lamellarstructures that differ in molecular size, degree of aromaticity, oxygencontent, nitrogen content, and the degree of cross-linking. Coal alsocontains volatile matter, fusain, mineral matter, and moisture. Themineral matter remains behind as ash when the coal is burned, and fusainis a mineral charcoal which is consumed during burning at hightemperatures in the presence of sufficient oxygen for completecombustion. Coal contains sulfur which is present as pyritic sulfur,inorganic sulfates and/or organic sulfur compounds. The presence ofsulfur in substantial quantities results in contamination of theatmosphere with sulfur oxides upon combustion which, upon reaction withatmospheric moisture, produce highly corrosive sulfurous acid and/orsulfuric acid. The mineral content of the coal, which may be -15 percentor higher in many instances, reduces the B.t.u. value of the raw coalper unit weight and this results in increased transportation costs.There is an additional cost when the ash-containing coal is burned asthe ash residue must be removed from the combustion zone and disposed ofin some manner.

The presence of fusain, mineral matter, and sulfur in substantialquantities also reduces the value of the coal. If these substances areremoved, the coal may be used for preparing high purity coke forspecialized purposes, such as in anodes to be used in the production ofaluminus. High purity coke for anodes has a much higher value than theimpure coke produced from the original coal.

In view of the foregoing and for still other reasons, it is desirable toreduce the fusain, mineral matter, and sulfur content of coal. Oneprocess for removing these substances involves solvation of thesolvent-soluble coal constituents including the bitumen and humincontents in an organic solvent, and then separating the insolublefusain, mineral matter, and inorganic sulfur from the coal solution.This process is largely ineffective for the removal of organicallycombined sulfur as it is soluble in the solvent.

A wide variety of organic solvents have been employed for solubilizingcoal. However, the solvents used heretofore have not been capable ofindirectly hydrogenating the solubilized coal to the extent required toproduce low boiling liquid products and it has been necessary to resortto direct hydrogenation with gaseous hydrogen. Direct hydrogenationrequires high temperatures and pressures and the presence of a catalystwhich tends to be poisoned by impurities in the coal. As a result, aneconomic method of hydrogenating and desulfurizing coal to produce a lowsulfur synthetic crude petroleum has not been available heretofore.

SUMMARY OF THE INVENTION The present invention provides for the firsttime an entirely satisfactory process for simultaneously solubilizingand hydrogenating coal.

The invention further provides a process for hydrogenating coal whichdoes not require a catalyst in the solvation vessel, or the use ofextremely high over-pressures of hydrogen. The partial hydrogenation ofthe solvent is accomplished outside of the coal solvation vessel, and inthe absence of substances which would poison or otherwise adverselyaffect the hydrogenation catalyst.

The invention further provides a process for solubilizing an unusuallyhigh percentage of the coal, and which maximizes the production ofvaluable liquid products and minimizes the production of low molecularweight gases and solid byproducts. It is possible to obtain a higheryield of the more valuable constituents of the coal, and a lowerpercentage is lost in processing.

The invention further provides for the substantially complete removal ofthe mineral ash constituents of the coal.

The invention further provides a greatly improved process for removingsulfur from coal, as both mineral sulfur and organically combined sulfurare removed. It is possible to reduce the sulfur content of the deashedsolubilized coal to well below 0.5 percent by weight, and often below0.1 percent by weight. Such low sulfur contents have not been achievedheretofore in prior art coal solubilization processes.

The invention further provides a continuous process for producingsynthetic crude from coal, as the liquid products produced in accordancewith the present invention are suitable for use as a feedstock to aprior art petroleum refinery. The used or dehydrogenated solvent may berecovered from the coal solution by fractionation, subjected to apartial hydrogenation step, and recycled in the process.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1A and 1B of the drawingsillustrate one presently preferred arrangement of apparatus for use inpracticing the process of the invention. FIG. 1B is a continuation ofFIG. 1A.

DETAILED DESCRIPTION OF THE INVENTION INCLUDING PREFERRED VARIANTSTHEREOF Referring now to the drawings, a partially hydrogenatedhydrocarbon solvent to be defined more fully hereinafter is passed fromstorage vessel 10 to mixer 11 via conduit 12 at a rate controlled byvalve 14. Finely divided coal in storage vessel 15 is also passed tomixer 11 via conduit 16 at a rate determined by meter l7. The relativefeed rates of solvent and coal are controlled so that the weight ratioof solvent to coal in mixer 11 is between about l:l and 20:1, andpreferably between 2:] and 5:1. The best results are usually obtainedwhen the weight ratio of solvent to coal is approximately 3:1.

The coal and solvent in mixer 11 are agitated with a motor drivenagitator l8, and the slurry thus prepared is passed to pump 19 viaconduit 13, and then via conduit 20 to gas-fired heater 21. The slurryflowing in coil 22 is heated to an elevated temperature which preferablyclosely approximates the desired initial temperature of solvation, andthe heated slurry is then withdrawn via conduit 23 and is passed tosolutizer 24.

While it is not essential when using partially hydrogenated solvents, itis usually preferred to carry out the solvation in the presence of addedgaseous hydrogen. When gaseous hydrogen is added, it may be passed intothe slurry flowing in conduit 20 upon opening valve 25 in conduit 26.

The solutizer 24 preferably operates under a superatmospheric pressurewhich is determined by the overpressure of gaseous hydrogen whenpresent, the vapor pressure of the solvent at the operating temperature,and/or the hydraulic pressure applied by pump 19. The solvationtemperature is determined by the initial temperatures of the slurry inconduit 23 and by the temperature control fluid supplied to coil 27 at arate controlled by valve 28 in conduit 29 and withdrawn via conduit 30.The solvent is contacted with the coal under the temperature andpressure conditions existing in solutizer 24 for a sufficient period oftime to solubilize and hydrogenate a substantial amount of extractablecarbonaceous material and to produce a solution which contains finelydivided fusain, mineral ash, and other insoluble constituents.

The coal solution containing the insoluble constituents is withdrawnfrom solutizer 24 via conduit 31 and is passed to header 33 which isprovided with a plurality of space outlets 34. The header 33 ispositioned in ash separator 35 a substantial distance beneath theinterface 36 between the relatively heavy sludge layer 37 and thelighter clarified coal solution 38. The sludge layer 37 contains mineralash, fusain and other insoluble material, and it is withdrawn viaconduit 39 at a rate controlled by valve 40. The sludge 37 is withdrawnat a rate to maintain the interface 36 substantially above the outlets34 on header 33. Inasmuch as the coal solution flowing in conduit 31 isat an elevated temperature and has a low viscosity, the heavierinsoluble material tends to settle out rapidly when it is passed intoash separator 35. While the mechanism is not fully understood at thepresent time, it is believed that injecting the solution into the heavysludge layer 37 tends to agglomerate the micron size solid particles ofinsoluble material and larger particles are formed which settle evenmore rapidly. As a result, the lighter clarified phase 38 issubstantially free of insoluble material and often it does not requirefiltering, and especially in instances where the entire deashed coalsolution is to be used as a fuel.

The clarified coal solution 38 is withdrawn from the top of ashseparator 35 via conduit 45 and, upon opening valve 46 and closingvalves 47 and 49, it is passed via conduit 44 to coil 51 in heatexchanger 52. A coolant such as water is supplied to heat exchanger 52via conduit 53 at a rate controlled by valve 54, and it is withdrawntherefrom via conduit 55. In instances where it is desired to filter theclarified coal solution for the purpose of removing additional insolublematerial, valve 46 is closed and valves 47 and 49 are opened, and theclarified coal solution 38 is passed via conduits 45 and 48 to filter56. The clarified and filtered coal solution is withdrawn via conduit 50and is passed to conduit 44, and then to coil 51 in heat exchanger 52.

The coal solution may be cooled i heat exchanger 52 to any suitabledesired temperature such as 75200 F. or higher, or to a temperaturewhich is suitable for feeding to atmospheric distillation tower 57. Thesolution is withdrawn via conduit 58 at a rate controlled by reducingvalve 59 and is passed into gas separator 60.

The gas separator 60 is partially filled with a liquid coal solutionphase 61 which has a vapor space 62 thereabove. The coal solutionflowing in conduit 58 contains excess hydrogen, hydrogen sulfideproduced by desulfurization of the coal during the solvation step,hydrocarbon gases, and other gases which are released into the vaporspace 62 upon reducing the pressure on the solution as it passes throughreducing valve 59. The pressure existing within vapor space 62 may be,for example, from substantially atmospheric pressure to 1 or 2atmospheres. The gases in vapor space 62 are withdrawn via conduit 63 ata rate controlled by valve 64. If desired, the gases may be passed to asour gas processing step, the sulfur content recovered, and the hydrogencontent recycled to conduit 26.

In instances where one or more light liquid fractions are not recoveredfrom the coal solution, it may be withdrawn from gas separator 60 viaconduit 68 upon closing valve 65 in conduit 66 and opening valve 67. Thedeashed, degassed and desulfurized coal solution withdrawn via conduit68 is very useful as a fuel. Inasmuch as it is normally liquid at roomtemperature, it may be readily pumped and transported by pipeline.

In most instances, it is desirable to recover at least the gasolinefraction and the light gas oil fraction from the coal solution as theseare valuable liquid products of commerce, and also a dehydrogenatedsolvent fraction for recycle in the process. This may be convenientlyaccomplished by closing valve 67 in conduit 68, opening valve 65 inconduit 66, and passing the deashed and degassed coal solution toatmospherical distillation tower 57.

As will be recognized by those skilled in this art, it is not necessarythat ash separator 35, filter 56, and heat exchanger 52 be operated atapproximately the same pressure as exists in solutizer 24. For example,pressure-reducing valve 59 may be relocated in conduit 31 and gasseparator 60 relocated immediately after the valve 59, and in suchinstances the ash separator 35, filter 56 and heat exchanger 52 may beoperated at approximately the same pressure as gas separator 60.

Atmospheric distillation tower 57 may be of a prior art type used inpetroleum refining for producing a plurality of hydrocarbon streams fromcrude oil. The construction and operation of such combinationatmospheric distillation towers is well known, and does not constitute apart of this invention. Distillation tower 57 may be operated, forexample, to produce a stream of normally gaseous hydrocarbons which iswithdrawn via conduit 69, a gasoline stream having a boiling point up to430 F. which is withdrawn via conduit 70, a light gas oil stream havinga boiling range of 430-700 F. which is withdrawn via conduit 71 forfurther refinery processing, and a residue or bottoms stream which iswithdrawn via conduit 73. The gases withdrawn via conduit 69 may be usedto fire heater 21 or for other fuel purposes; and the gasoline streamwithdrawn via conduit 70 may be used for internal combustion enginefuel.

The bottoms fraction withdrawn via conduit 73 is passed to vacuumdistillation tower 89. in that tower, a heavy gas oil fractioncontaining dehydrogenated solvent and having a boiling range of, forexample, 560950 F. is withdrawn and passed via conduit to catalyticcracker unit 78 wherein it is cracked and fractionated into lighterproducts including, for example, a gasoline fraction which is withdrawnvia conduit 79, as well as other conventional catalytic cracker productswhich are not shown. The bottom stream withdrawn from vacuumdistillation tower 89 via conduit may be recycled in the process viaconduits 97 and 82 for further thermal cracking and hydrogenation toproduce lighter liquid products upon opening valve 96 and closing valve98. It also may be withdrawn via conduit 99 upon closing valve 96 andopening valve 98 and used as a low sulfur fuel.

The bottoms product withdrawn via conduit 100 from catalytic crackerunit 78 and having a boiling range of from 700-900 F. consists of slurryoil produced in said catalytic cracker unit and dehydrogenated recyclesolvent. The bottoms product is passed to clarifier 101, from whichsludge is removed via conduit 104, and then passed via conduit 102 at arate controlled by valve 103 to hydrogenation unit 80.

If required, makeup solvent may be introduced via conduit 106 intoconduit 102 at a rate controlled by valve 107'. Further, if excesssolvent is flowing in conduit 102, it may be conveniently removed viaconduit 106 at a rate controlled by valve 107. Such makeup solvent as isrequired is usually a small percentage of that flowing through thesystem such as ll0 percent, and is usually approximately 5-6 percent.Hydrogen is fed via conduit 108 at a rate controlled by valve 109 intohydrogenation unit 80. The partially hydrogenated solvent is thenwithdrawn via conduit 82 and is passed to solvent storage 10 for reusein the process.

The carbonaceous material that is solubilized may be coal, whichpreferably is of a rank lower than anthracite, such as subanthracite,bituminous, subbituminous, and lignite or brown coal. Peat also may beused. The particles size of the coal may vary over wide ranges and ingeneral the particles need only be sufficiently small to be slurried inthe solvent and pumped. For instance, the coal may have an averageparticle size of onefourth inch in diameter or larger in some instances,and as small as minus 200 mesh (Tyler Screen) or smaller. The mostpractical particle size is often between minus 30 mesh and minus 100mesh as less energy is required for grinding and yet the particles aresufficiently small to achieve an optimum rate of solubilization. Theparticle size is not of great importance provided extremely largeparticles are not present as the solvent penetrates the coal particlesrapidly. The carbonaceous material that is hydrogenated in accordancewith the invention is derived from coal, i.e., it may be coal,solubilized coal which is dissolved in a solvent other than thepartially hydrogenated hydrocarbon solvent, solid deashed coal preparedby a prior art deashing process, partially hydrogenated coal which isbeing recycled, etc.

A partially hydrogenated hydrocarbon solvent is employed that has beensubjected to a partial hydrogenation step prior to intimately contactingit which the particulate coal and/or carbonaceous material derivedtherefrom. The hydrocarbon solvent contains polycyclic hydrocarbonshaving normal boil ing points of about 425l000 F. and at least twocondensed benzene rings before the partial hydrogenation step, and afterpartial hydrogenation, it contains polycyclic hydrocarbons wherein atleast one of the said condensed benzene rings is retained and hydrogenis added during the partial hydrogenation to at least one condensedbenzene ring adjacent thereto. Thus, the partially hydrogenatedhydrocarbon solvent contains polycyclic hydrocarbons having anaromatic-naphthenic used ring structure wherein a benzenoid ring and anonbenzenoid or naphthenic ring adjacent thereto are fused. It isunderstood that still other naphthenic or benzenoid rings may be presentin the polycyclic hydrocarbon molecule, and they may be either fused tothe foregoing two minimum rings or they may be located in other portionsof the molecule. The solvent preferably contains polycyclic hydrocarbonshaving about 2-4 benzene rings before partial hydrogenation, and atleast one of the benzene rings is retained and 1-3 benzene rings arehydrogenated to produce naphthenic rings during the partialhydrogenation step.

The solvent to be partially hydrogenated may be a byproduct streamproduced in normal petroleum refinery operations having a boiling rangeof about 430-1000 F., e.g., a catalytic cracker recycle stock such aslight recycle catalytic cracker oil, heavy recycle catalytic cracker oiland clarified catalytic cracker slurry oil, thermally cracked petroleumstocks, and lubricating oil aromatic extracts such as bright stockphenol extract. The boiling range of the byproduct petroleum stream ispreferably between about 600 and 1000 F., and should be about 700-900 F.for better results in most instances. Refractory highly aromatic streamswherein the aromatic constituents contain two or more fused benzenerings per molecule and make up at least 50 percent by weight of thesolvent are preferred, and for better results the aromatic constituentsshould be present in an amount of at least 80-95 percent by weight.Clarified catalytic cracker slurry oil is an excellent solvent.

The amount of hydrogen that is added to the solvent during the partialhydrogenation step should be sufficient to hydrogenate a substantialnumber of the fused benzene rings in the polycyclic hydrocarbon content,but insufficient to hydrogenate all of the fused benzene rings. Forinstance, when the polycyclic hydrocarbons have about 2-4 condensedbenzene rings before partial hydrogenation, at least one of the benzenerings is retained in the molecule and 1-3 benzene rings may behydrogenated to produce naphthenic rings during the partialhydrogenation step. As a general rule, approximately 100-1000, andpreferably about 200-700 standard cubic feet of hydrogen per barrel ofsolvent added, but smaller or larger amounts of hydrogen may be addeddepending on the desired degree of hydrogenation and the number of fusedbenzene rings which are present. In instances where the solvent isclarified catalytic cracker slurry oil, it is usually preferred thatapproximately 400-500 standard cubic feed of hydrogen per barrel ofslurry oil be added during the partial hydrogenation step.

Prior art hydrogenation catalysts may be employed such as a mixednickel-molybdenum catalyst. Also, the prior art temperature andpressures for such hydrogenation reactions may be employed, e.g., ahydrogen pressure of about 100-1000 p.s.i.g. and a temperature of about400-800 F. The pressure is preferably about 200-500 p.s.i.g. and thetemperature approximately 550-650 F. As a general rule, thehydrogenation is usually continued until approximately 50 percent of theethylenic double bonds contained in the solvent have been saturated oruntil a quantity of hydrogen such as discussed above has been added.

The presence of added elemental hydrogen is not always necessary, but itis usually beneficial and aids in more rapid and complete solubilizationand/or hydrogenation. In a continuous process, the feed may include0.1-2 percent and preferably 0.25-1 percent by weight of hydrogen basedupon the weight of coal or carbonaceous material derived therefrom. Theexcess hydrogen which does not enter into the solubilization and/orhydrogenation reaction may be recovered from the coal solution andrecycled if desired, and thus higher percentages than 2 percent byweight may be used such as up to 5 percent weight. The hydrogen contentof the vapor phase in contact with the liquid solvent phase may be 5-50percent and is preferably about 10-35 percent by volume, but may behigher or lower. However, the higher the partial pressure of hydrogen,the faster the solubilization and/or hydrogenation reaction as morehydrogen is available in the solvent.

The temperature should be sufficiently high to result in a fastsolvation and/or hydrogenation rate. The upper limit is the temperatureat which the coal and/or carbonaceous material derived therefrom iscoked and/or the organic solvent is decomposed. The temperature may beabout 550-l0 00 F., and preferably is at least 650 F. to 700 F. In mostinstances, the temperature should be about 650-900 F. and, for bestresults, about 700-850 F The solvation temperature should not besufficiently high to result in substantial coking within the period oftreatment. The coking temperature varies from coal to coal, and usuallycoals having a higher rank also have a higher decomposition or cokingtemperature. Oklahoma bituminous coal usually cokes at about 800-840 F.,and more highly volatile coals such as the Wyoming coals usually coke atlower temperatures. In instances where a tubular reactor is employed anda slurry of coal in the solvent is passed through the tubes on acontinuous basis, somewhat higher temperatures may be employed due tothe dynamic nature of the system. Also, rate of flow through the tubesis sufficiently fast to reduce coking on the tube surfaces.

The solvent is contacted with the coal and/or carbonaceous materialderived therefrom for a sufficient period of time to solubilize and/orhydrogenate a substantial amount of the extractable material in thecoal. For example, the solvent may be contacted with the coal over about0.1-2 hours. The contact period should not be more than about 0.2-1 hourfor economic reasons; and is preferably 0.25-0.5 hour.

The weight ratio of solvent to coal and/or carbonaceous material derivedtherefrom may vary over wide ranges. The minimum weight ratio of solventto coal and/or carbonaceous material derived therefrom for effecting aworthwhile amount of hydrogenation is about 0.2: l and the upper limitis practical in nature and may be up to about 20: 1. The minimum ratioof solvent to coal for solvation is usually about 1:1 or 2:1 and theupper limit may be as high as 15:1 or 20:1. There is little improvementin the degree of extraction beyond solvent to coal weight ratios of 5:1or 10:1, and as the cost of handling the solvent increases with theamount used per unit weight of coal, the lowest ratio necessary to givea desired degree of extraction is preferred. Usually, this is a solventto coal weight ratio between about 2:1 and 5: 1.

The pressure in solutizer 24 is at least sufficient to maintain liquidphase conditions and it may be as high as 10,000 pounds per square inchabsolute (p.s.i.a.), and is preferably about 1,000-5,000 p.s.i.a. formost solvents. The pressure should be sufficient to provide a solventdensity of at least 0.5 g./cc. and preferably at least 0.6 g./cc. Thereis no upper limit on the solvent density within the foregoing pressurerange as the highest solvent density that can be achieved underpractical operating conditions is usually more satisfactory. Thesolvents defined herein have a solvent density of about 0.5-0.9 g./cc.,and preferably about 0.6-0.7 g./cc., under the practical temperature andpressure conditions.

The pressure on the system is not important in the absence of a hydrogenoverpressure provided the solvent has the necessary minimum density. 1fthe solvent density is too low, then it is necessary to resort topressure to increase the density. Usually pressurized hydrogen ispreferred as a pressurizing medium, but other gases or gaseous mixturesmay be employed. Also, the pressure may be imposed by suitablehydrostatic means such as a high pressure pump.

The coal solution produced in accordance with the invention may beseparated from the undissolved mineral ash, fusain and other insolubleconstituents following prior art practices. For instance, it is possibleto allow the coal solution to settle for a suitable period of time suchas %l hour in separator 35 under the conditions of solubilization, andthen withdraw the heavy phase 37 containing the undissolved material inthe form of a slurry or liquid-appearing phase. It is also possible tofilter the solution and remove the ash constituents, or the ashconstituents may be separated by centrifuging.

The process of the invention is very flexible and is capable ofproducing a liquid coal solution which is suitable for use as a bunkerfuel without the need for preheating, a semisolid to solid coal which isliquefiable upon heating with steam and also may be used as a heavy fueloil such as bunker fuel, or a friable coal product that may be used as asolid fuel in the same manner as conventional coal. For instance, thesolution withdrawn from gas separator 60 via conduit 68 is normallyliquid at room temperature and does not require heating for pumping, andthe product withdrawn from vacuum distillation tower 89 via conduit 95may be substantially free of distillate fractions and may be a friablesolid when cooled to room temperature. In all instances, the productsproduced by the process of the invention are deashed, and generally arereduced in sulfur content to low levels, such as 0. l-l percent byweight.

The invention is also unique in its ability to convert a largepercentage of the raw coal into light distillate hydrocarbon fractionswhich are suitable for use as fuel for internal combustion engines orlight heating oils. After removal of the light distillable fractions andheavy gas oil containing dehydrogenated solvent from the coal solution,the higher boiling fraction may be recycled for additional hydrogenationand/or thermal cracking to lighter fractions. When desired,substantially all of the coal that is solubilized may be converted intousable light distillate fractions and this may be accomplished withoutthe need for unusually high pressure anywhere in the system. Also,catalyst poisoning is not a problem due to the hydrogenation ofdistillate fractions which contain substantially no metal compounds andvery little sulfur.

The dehydrogenated hydrocarbon solvent may be recovered as a distillatefraction and, after partial hydrogenation, is recycled indefinitely. Themake up solvent that is required is usually approximately -10 percent byweight of the solvent flowing through the system. The make up solventcan be obtained from the high boiling liquid fractions that are producedand the process is capable of being self-sufficient insofar as thesolvent requirements are concerned.

As a general rule, the amount of partially hydrogenated hydrocarbonsolvent that is required for hydrogenating a previously solubilized ordeashed coal fraction is substantially less than that required for bothsalvation and hydrogenation of the raw coal. When the coal has beenpreviously solubilized or deashed, usually about 0.23 parts by weight ofthe solvent for each part by weight of the deashed coal is sufficient toachieve a satisfactory degree of hydrogenation. lt is understood thatthe degree of hydrogenation varies with the amount of available hydrogenin the partial hydrogenated hydrocarbon solvent. By varying the amountof hydrogen that is added to each barrel of the solvent in the partialhydrogenation step and/or the ratio by weight of solvent to coal, theamount of coal that is converted to light distillable fractions may becontrolled to some extent.

in instances where a previously deashed solid coal is used as afeedstock, it is merely substituted for the raw coal in vessel 15. Ininstances where a solution of previously deashed coal in a solvent otherthan the partially hydrogenated hydrocarbon solvent is used as afeedstock, the solution may also be fed to vessel and the requiredamount of partially hydrogenated hydrocarbon solvent is added thereto inmixer 1]. in each instance, the remainder of the process may be aspreviously described for raw coal with the exception of there being noneed for withdrawing a heavy phase 37 from ash separator 35.

The following examples further illustrate the process of the invention.

EXAMPLE! This example illustrates the preparation of a partiallyhydrogenated hydrocarbon solvent for use in practicing the invention.

The feedstock was a clarified catalytic cracker slurry oil which wasproduced in normal petroleum refinery operations. The slurry oil had adistillation range of 700l ,000 F. and an AP! gravity of2. l.

The slurry oil was partially hydrogenated in a laboratory rockingautoclave at a temperature of 600 F. and under a hydrogen pressure of500 p.s.i.g. in the presence of a mixed nickel-molybdenum hydrogenationcatalyst. The hydrogenation was continued until hydrogen was consumed inan amount equivalent to 600 standard cubic feet per barrel of the slurryoil charge stock. The hydrogenation was terminated, the partiallyhydrogenated slurry oil was recovered and analyzed, and the analysis wascompared with that of the charge stock. The following data was obtained:

The partially hydrogenated slurry oil produced in accordance with thisexample was used in example ll.

EXAMPLE ll This example illustrates the solvation and hydrogenation of asubbituminous Wyoming coal using the partially hydrogenated slurry oilproduced in accordance with example I as a solvent and indirecthydrogenating agent.

The pressure vessel was a 1 liter Paar autoclave which was provided witha valved conduit for withdrawing a heavy phase from the lower end, avalved conduit for withdrawing a light phase from the upper end, and apressure gauge. The autoclave was charged with 730 grams of a slurrycontaining in part by weight of the dry coal ground to minus 65 mesh andthree parts by weight of the partially hydrogenated slurry oil. Theautoclave was then pressurized with gaseous hydrogen to 500 p.s.i.g.,and the temperature was raised to 700 F. These conditions weremaintained for one-half hour, during which time about percent of theextractable carbonaceous matter in the coal was solubilized, and thenthe solution was cooled to F. and filtered to remove the undissolvedresidue. The undissolved residue was collected and analyzed, and theanalysis was compared with that for the initial coal. The results appearbelow in table ll.

TABLE ll Volatile Matter Fixed Carbon Material wt. 96 Ash, wt. 70 wt.it:

initial coal 45.8 6.6 47.6 Undissolved coal residue 14.1 60.1 25.8

The data in table Ill show that the coal was hydrogenated to produceapproximately one-third by weight of hydrocarbons boiling in thegasoline range (up to 430 F.), one-third by weight of hydrocarbonsboiling in the light gas-oil range (430700 F.), and one-third by weightof higher boiling hydrocarbon products.

An analysis of the distillate fractions showed the sulfur content to beless than 0.1 percent, as compared with approximately 0.8-0.9 sulfur inthe initial coal. Thus, the process is effective for the removal of bothmineral sulfur and organic sulfur. The analysis of the fraction boilingat 700l ,000 F. gave the following results:

Carbon, wt. 91.7 Hydrogen, wt. 8.2 Sulfur, wt. less than 0.1 Gravity,+APl 2.4

The above analysis is substantially the same as that for the clarifiedslurry oil before it was partially hydrogenated in accordance withexample I. This demonstrates that the hydrogen added to the slurry oilin the partial hydrogenation step of example was transferred to the coalduring the solvation and hydrogenation step of this example.

The fraction distilling at 700l,000 F. may be partially hydrogenated inaccordance with example l and reused as a solvent.

EXAMPLE III This example illustrates the solvation of coal whenemploying the apparatus shown in FIGS. 1A and 1B of the drawings.

Dry Oklahoma bituminous coal (Stigler Seam, Evans Coal Company) having aparticle size of minus 65 mesh and partially hydrogenated clarifiedcatalytic cracker slurry oil having a boiling range before hydrogenationof 700-900 F. are fed to mixer 11 at feed rates to provide three partsby weight of the slurry oil for each part by weight of the coal. Thesuspension of coal in the solvent is passed to pump 19 via conduit 13,and then via conduit 20 to heating coil 22 in heater 21 where thetemperature is raised to 750 F. Elemental hydrogen in an amount of 0.5part by weight based upon the weight of the coal is added via conduit 26to the suspension flowing in conduit 20.

The heated hydrogen-containing slurry is withdrawn via conduit 23, andis passed to solutizer 24 which is a tube still operating at a pressureof 1,5000 p.s.i.g., at a feed rate to provide a residence time ofminutes. A heating fluid is supplied to coil 27 to maintain atemperature of 750 F. in solutizer 24 during the 30 minutes residencetime therein during which approximately 95 percent by weight of thecarbonaceous matter in the coal is solubilized. Coal solution containingsuspended micron size particles or mineral ash, fusain and otherinsoluble constituents is withdrawn as a fluid phase via conduit 31, andis passed to header 33 in ash separator 35. The header 33 is positionedbelow the surface 36 of sludge layer 37 whereby the micron sizeparticles of insoluble constituents are agglomerated as the coalsolution is ejected via outlets 34. The average residence time for thesolution in ash separator is 30 minutes, and this is sufficient time toallow substantially all of the insoluble constituents to be agglomeratedand retained in the heavy sludge layer 37. The sludge layer 37 iswithdrawn via conduit 39 as a fluid phase at a rate sufficient tomaintain the interface 36 at the level illustrated in the drawing.

The lighter clarified phase 38 of coal solution in the upper section ofash separator 35 contains very small amounts of micron size insolublematerial, and this is removed by passing thecoal solution to filter 56via conduits 45 and 48. The clarified and filtered coal solution iswithdrawn via conduit 50 and is passed via conduit 44 to heat exchanger52 where the temperature is reduced to below the boiling point ofgasoline, and the cooled solution is passed to gas separator 60 viaconduit 58. The pressure in gas separator 60 is about 1 to 2atmospheres. Excess hydrogen and gases produced during the solvation arewithdrawn via conduit 63 and the degassed coal solution is passed toatmospheric distillation tower 57 via conduit 66.

A light or normally gaseous hydrocarbon fraction is withdrawn fromdistillation tower 57 via conduit 69 and is used as fuel in the processsuch as in heater 21 and for other heating purposes. A gasoline fractionis withdrawn via conduit 70 for sale as motor fuel and a light gas oilfraction is withdrawn via conduit 71 for subsequent refinery processing.The bottoms fraction from distillation tower 57 is passed to vacuumdistillation tower 89 via conduit 73 and a heavy gas oil containingdehydrogenated solvent is separated therefrom via conduit and is passedto catalytic cracker unit 78. The heavy gas oil fraction is cracked toproduce lighter products, including gasoline, for subsequent processingor for sale.

A slurry oil fraction is withdrawn from catalytic cracker unit 78 viaconduit 100, passed to clarifier 101 where a clarified slurry oilfraction is prepared, and the clarified slurry oil is withdrawn viaconduit 102 and is passed to hydrogenation unit 80. Makeup solvent,which is clarified catalytic cracker slurry oil having a boiling rangeof 700900 F., is supplied to conduit 102 via conduit 106 in an amount ofabout 6 percent by weight of the solvent flowing through the system.Hydrogen is fed via conduit 108 and is introduced into the hydrogenationunit 80 at a rate to provide 400 standard cubic feet of hydrogen perbarrel in the partially hydrogenated slurry oil that is withdrawn viaconduit 82.

The bottoms fraction from vacuum distillation tower 89 is passed toconduit 82 via conduits and 97 for recycle in the process where it issubjected to additional hydrogenation and thermal cracking to producelighter hydrocarbon fractions. When desired, a portion or all of thebottoms from distillation tower 89 may be withdrawn via conduits 95 and99 and may be used as a low sulfur fuel.

EXAMPLE IV This example illustrates the hydrogenation of carbonaceousmaterial which was previously derived from coal by solubilization in asolvent other than the partially hydrogenated hydrocarbon solvent of theinvention. The pressure vessel emgloyed in this example was the same asthat used in example ll.

The autoclave was partially filled with 540 grams of pyridine and gramsof minus 65 mesh dry Oklahoma bituminous coal which had a sulfur contentof approximately 2 percent and a mineral ash content of approximately 11per cent. The autoclave was sealed, the air was evacuated from the vaporspace above the charge, and the vapor space was pressurized withhydrogen gas to an initial hydrogen pressure of 750 p.s.i.g. The sealedautoclave was heated and agitated in a rocking heater to provide asolvent temperature of 640 680 F., and the pressure rose rapidly to amaximum pressure of 4,800 p.s.i.g. The heating and agitation wascontinued for 1 hour, and then the solution was allowed to settle for 30minutes. The heavy phase, which was a fluid slurry of undissolved coal,ash and a small amount of the dissolved coal in pyridine, was withdrawnby opening the valve in the conduit leading from the bottom of theautoclave. The solution of coal remaining after removing the slurrycontained approximately 1 percent by weight of sulfur and about 0.2percent by weight of ash. Under these conditions, 49 percent by weightof the coal was dissolved in the pyridine solvent, and it was recoveredas a friable solid by evaporation of the pyridine.

Deashed and desulfurized coal prepared by the above process is admixedwith three parts by weight of the partially hydrogenated clarifiedslurry oil produced in accordance with example I, and the autoclave ischarged with 700 grams of the mixture. The autoclave is sealed, and thetemperature is raised to 700 F. by heating and agitating in the rockingheater. The pressure in the autoclave is 1,500 p.s.i.g. The heating andagitation is continued for one-half hour. The fluid solution iswithdrawn from the autoclave and upon fractional distillation,approximately one-third by weight of the deashed coal charge is obtainedas liquid hydrocarbons boiling within the light gas oil range. Thesulfur contents of the gasoline and light gas oil fractions are lessthan about 0.1 percent and about 0.3 percent by weight, respectively.

EXAMPLE V This example illustrates the hydrogenation of a solution ofsolubilized coal in a solvent other than the partially hydrogenatedhydrocarbon solvent of the present invention. The autoclave employed inthis example is the same as that described in example ll.

The general procedure of example 1V is repeated with the exception ofsubstituting the clarified slurry oil described in example 1 for thepyridine as a solvent. The slurry oil is not partially hydrogenated, andit is used as a solvent in this example as produced in the refineryoperation. The hydrogen overpressure is 750 p.s.i.g., the maximumpressure employed is 1,750 p.s.i., and the solvation temperature is 750F. The au toclave is heated and agitated under these conditions for 1hour, and then the coal solution is allowed to settle for onehalf hour.The settled ash and other insoluble constituents are removed leaving asolution of solubilized coal in the slurry oil. Approximately 80 percentby weight of the coal is dissolved.

Upon removal of one-half of the solution from the autoclave andevaporation of the solvent under reduced pressure, it is found thatsubstantially no light distillate fraction is present. The deashed coalis a hard and friable solid after removal of the solvent.

Three parts by weight of the partially hydrogenated slurry oil solventprepared in accordance with example 1, based upon the weight of coaldissolved in the solution remaining in the autoclave, is added and theautoclave is closed. The autoclave is agitated and heated at 750 F. foran additional hour at a pressure of 1,500 p.s.i.g., and then cooled toroom temperature. The coal solution is very fluid and it is apparentthat a substantial degree of hydrogenation occurs. Upon subjecting thehydrogenated coal solution to fractional distillation, it is found thatat least one-third of the initial weight of solubilized coal isconverted to a light distillate boiling within the gasoline range, andan additional one-third is converted to a heavier distillate boilingwithin the light gas oil range. Thus, it is possible to add thepartially hydrogenated hydrocarbon solvent to a solution ofunhydrogenated coal in another solvent, and then partially hydrogenatethe solubilized coal and produce light distillate fractions withoutfirst recovering the deashed coal.

What is claimed is:

l. A process for hydrogenating feedstock including coal and carbonaceousmaterial derived therefrom comprising subjecting said feedstock to atemperature of about 5501,000 F. in the presence of a partiallyhydrogenated hydrocarbon solvent selected from the group consisting ofpartially hydrogenated catalytic cracker recycle stocks, thermallycracked stocks, and lubricating oil aromatic extracts whereby hydrogenis released by the solvent and the carbonaceous material ishydrogenated, the hydrocarbon solvent containing a mixture of polycyclichydrocarbons having normal boiling points of about 4251,000 F. and atleast two condensed benzene rings before partial hydrogenation, and thepartially hydrogenated hydrocarbon solvent containing polycyclichydrocarbons wherein at least one of the said condensed benzene rings isretained and hydrogen is added to at least one condensed benzene ringadjacent thereto during the partial hydrogenation.

2. The process of claim 1 wherein the feedstock to be hydrogenated isprepared by solubilizing coal in a solvent other than the partiallyhydrogenated hydrocarbon solvent, and thereafter the solubilized coal ishydrogenated in the presence of the partially hydrogenated hydrocarbonsolvent.

3. The process of claim 1 wherein each part by weight of the feedstockis hydrogenated in the presence of about 02-20 parts by weight of thepartially hydrogenated hydrocarbon solvent.

4. The process of claim 1 wherein the feedstock is subjected to atemperature of about 650900 F. in the presence of the partiallyhydrogenated hydrocarbon solvent.

5. The process of claim 1 wherein the hydrocarbon solvent containspolycyclic hydrocarbons having about 2-4 condensed benzene rings beforepartial hydrogenation, and at least one of said benzene rings isretained and 1-3 benzene rings are hydrogenated to produce naphthenicrings during partial hydrogenation.

6. The process of claim 1 wherein the partially hydrogenated hydrocarbonsolvent is partially hydrogenated catalytic cracker slurry oil.

7. The process of claim 1 wherein each part by weight of the feedstockis subjected to a temperature of about 650-900 F. in the presence ofabout 02-20 parts by weight of the partially hydrogenated hydrocarbonsolvent.

8. The process of claim 7 wherein the partially hydrogenated hydrocarbonsolvent is partially hydrogenated catalytic cracker slurry oil.

9. The process of claim 8 wherein each part by weight of the feedstockis subjected to a temperature of about 700-850 F. in the presence ofabout 25 parts by weight of the partially hydrogenated catalytic crackerslurry oil.

10. The process of claim 1 wherein at least one light distillatefraction is separated from the hydrogenated feedstock subsequent to thehydrogenation step.

11. The process of claim 10 wherein at least one distillate fractionheavier than the said light fraction is subsequently separated from thehydrogenated feedstock, said heavier distillate fraction containingheavy gas oil and dehydrogenated hydrocarbon solvent, and said heavierdistillate fraction is catalytically cracked to produce lower boilingproducts and catalytic cracker recycle stock.

12. The process of claim ll wherein the catalytic cracker recycle stockis subjected to partial hydrogenation, and the partially hydrogenatedcatalytic cracker recycle stock thus prepared is used as a partiallyhydrogenated hydrocarbon solvent to hydrogenate additional feedstock.

13. The process of claim 1 wherein the hydrocarbon solvent contains amixture of polycyclic hydrocarbons having about 24 condensed benzenerings before partial hydrogenation and at least one of said benzenerings is retained and 1-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation, each part by weight ofthe feed stock is subjected to a temperature of about 650900 F. in thepresence of about 02-20 parts by weight of the partially hydrogenatedhydrocarbon solvent, and at least one light distillate fraction and atleast one heavier distillate fraction are separated from thehydrogenated feedstock, said heavier distillate fraction containing gasoil and dehydrogenated hydrocarbon solvent.

14. The process of claim 13 wherein the partially hydrogenatedhydrocarbon solvent is partially hydrogenated catalytic cracker slurryoil.

15. The process of claim 14 wherein said heavier distillate fraction iscatalytically cracked to produce lower boiling products and catalyticcracker slurry oil, and the catalytic cracker slurry oil thus producedis partially hydrogenated and used as a partially hydrogenatedhydrocarbon solvent to hydrogenate additional feedstock.

16. A process for hydrogenating and deashing coal comprising intimatelycontacting the coal in particulate form with a partially hydrogenatedhydrocarbon solvent selected from the group consisting of partiallyhydrogenated catalytic cracker recycle stocks, thermally cracked stocks,and lubricating oil aromatic extracts to produce a solution containingsolubilized hydrogenated coal and suspended insoluble material includingash, the partially hydrogenated hydrocarbon solvent being contacted withthe coal at a temperature of about 550-1,000 F. and at a solvent densityof at least 0.5 g./cc., whereby hydrogen is released and the coal issolubilized therein and hydrogenated, the hydrocarbon solvent beingsubjected to partial hydrogenation prior to contacting it with the coal,the hydrocarbon solvent containing a mixture of polycyclic hydrocarbonshaving normal boiling points of about 425- l,000 F. and at least twocondensed benzene rings before the partial hydrogenation thereof, thepartially hydrogenated hydrocarbon solvent containing a mixture ofpolycyclic hydrocarbons wherein at least one of the said condensedbenzene rings is retained and hydrogen is added to at least one of thesaid condensed benzene rings adjacent thereto, and separating theinsoluble material from the hydrogenated coal solution.

17. The process of claim 16 wherein the partially hydrogenatedhydrocarbon solvent is contacted with the coal in the presence ofelemental hydrogen.

18. The process of claim 16 wherein each part by weight of the coal iscontacted with about 0.2-20 parts by weight of the partiallyhydrogenated hydrocarbon solvent.

19. The process of claim 16 wherein the coal is contacted with thepartially hydrogenated hydrocarbon solvent at a temperature of at least650 F.

20. The process of claim 16 wherein the hydrocarbon solvent contains amixture of polycyclic hydrocarbons having about 2-4 condensed benzenerings before partial hydrogenation, and at least one of said benzenerings is retained and 1-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation.

21. The process of claim 16 wherein the partially hydrogenatedhydrocarbon solvent is partially hydrogenated catalytic cracker slurryoil.

22. The process of claim 16 wherein each part by weight of the coal iscontacted in the presence of elemental hydrogen at a temperature of atleast 650 F. with about 02-20 parts by weight of the partiallyhydrogenated hydrocarbon solvent for about 0.1-2 hours.

23. The process of claim 22 wherein the partially hydrogenatedhydrocarbon solvent is partially hydrogenated catalytic cracker slurryoil.

24. The process of claim 23 wherein each part by weight of the coal iscontacted with about 2-5 parts by weight of the partially hydrogenatedcatalytic cracker slurry oil in the presence of elemental hydrogen at atemperature of about 700-850 F. and the solvent density is at least 0.6g./cc.

25. The process of claim 16 wherein at least one light distillatefraction is separated from the hydrogenated coal solution.

26. The process of claim 25 wherein at least one distillate fractionheavier than said light fraction is subsequently separated from thehydrogenated coal solution, said heavier fraction containing heavy gasoil and dehydrogenated hydrocarbon solvent, and said heavy distillatefraction is catalytically cracked to produce lower boiling products andcatalytic cracker recycle stock.

27. The process of claim 26 wherein the catalytic cracker recycle stockis subjected to partial hydrogenation, and the partially hydrogenatedcatalytic cracker recycle stock thus prepared is used as a partiallyhydrogenated hydrocarbon solvent to solubilize and hydrogenateadditional coal.

28. The process of claim 16 wherein the hydrocarbon solvent contains amixture of polycyclic hydrocarbons having about 2-4 condensed benzenerings before partial hydrogenation and at least one of said benzenerings is retained and l-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation, each part by weight ofthe coal is contacted for about 0.1-2 hours with about O.220 parts byweight of the partially hydrogenated hydrocarbon solvent in the presenceof elemental hydrogen and at a temperature of at least 650 F., thesolvent density is at least 0.6 g./cc. and at least one light distillatefraction and at least one heavier distillate fraction are separated fromthe solution of hydrogenated coal, said heavier distillate fractioncontaining gas oil and dehydrogenated hydrocarbon solvent.

29. The process of claim 28 wherein the partially hydrogenatedhydrocarbon solvent is partially hydrogenated catalytic cracker slurryoil.

30. The process of claim 29 wherein each part by weight of the coal iscontacted with about 2-5 parts by weight of the partially hydrogenatedcatalytic cracker slurry oil, said heavier distillate fraction iscatalytically cracked to produce lower boiling products and catalyticcracker slurry oil, and the catalytic cracker slurry oil thus producedis partially hydrogenated and used to solubilize and hydrogenateadditional coal.

, UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No.3,607,718 Dated September 1. 7

Inventor(s) William M. Leaders; Jack'W. Roach It 'is certified thaterror appears in the above-identified patent and that said LettersPatent are hereby corrected as shown below:

Column 1, line 35, "aluminus" should read aluminum Column 3, line 27,"i" should read in Column 4-, line 32, "recycle" should read recycledlines 48 and 49, "su-" should read suband "banthracite" should readanthracite Column 5, line 4-9, before "added" insert is line 54, "feed"should read feet Column 6, lines 14 and l5, "l0" and "00 F." should readColumn 7, line 29, "distillable" should read distillate line 58,"partial" should read partially line 62, "distillable" should readdistillate Column 9, in the last line of the second table appearingtherein, "Gravity, i-API" should read Gravity, API

line 61, 1,5000" should read 1,500

Column 10, line 57, loyed" should read ployed Signed and sealed this25th day of April 5972 (SEAL IEDL IARD I IQFLJETCHJTR, JR. R BERTGGTTSCHALK flttosting Oif'ice-I' Commissionerof Patents

2. The process of claim 1 wherein the feedstock to be hydrogenated isprepared by solubilizing coal in a solvent other than the partiallyhydrogenated hydrocarbon solvent, and thereafter the solubilized coal ishydrogenated in the presence of the partially hydrogenated hydrocarbonsolvent.
 3. The process of claim 1 wherein each part by weight of thefeedstock is hydrogenated in the presence of about 0.2-20 parts byweight of the partially hydrogenated hydrocarbon solvent.
 4. The processof claim 1 wherein the feedstock is subjected to a temperature of aboUt650*-900* F. in the presence of the partially hydrogenated hydrocarbonsolvent.
 5. The process of claim 1 wherein the hydrocarbon solventcontains polycyclic hydrocarbons having about 2-4 condensed benzenerings before partial hydrogenation, and at least one of said benzenerings is retained and 1-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation.
 6. The process of claim 1wherein the partially hydrogenated hydrocarbon solvent is partiallyhydrogenated catalytic cracker slurry oil.
 7. The process of claim 1wherein each part by weight of the feedstock is subjected to atemperature of about 650*-900* F. in the presence of about 0.2-20 partsby weight of the partially hydrogenated hydrocarbon solvent.
 8. Theprocess of claim 7 wherein the partially hydrogenated hydrocarbonsolvent is partially hydrogenated catalytic cracker slurry oil.
 9. Theprocess of claim 8 wherein each part by weight of the feedstock issubjected to a temperature of about 700*-850* F. in the presence ofabout 2-5 parts by weight of the partially hydrogenated catalyticcracker slurry oil.
 10. The process of claim 1 wherein at least onelight distillate fraction is separated from the hydrogenated feedstocksubsequent to the hydrogenation step.
 11. The process of claim 10wherein at least one distillate fraction heavier than the said lightfraction is subsequently separated from the hydrogenated feedstock, saidheavier distillate fraction containing heavy gas oil and dehydrogenatedhydrocarbon solvent, and said heavier distillate fraction iscatalytically cracked to produce lower boiling products and catalyticcracker recycle stock.
 12. The process of claim 11 wherein the catalyticcracker recycle stock is subjected to partial hydrogenation, and thepartially hydrogenated catalytic cracker recycle stock thus prepared isused as a partially hydrogenated hydrocarbon solvent to hydrogenateadditional feedstock.
 13. The process of claim 1 wherein the hydrocarbonsolvent contains a mixture of polycyclic hydrocarbons having about 2-4condensed benzene rings before partial hydrogenation and at least one ofsaid benzene rings is retained and 1-3 benzene rings are hydrogenated toproduce naphthenic rings during partial hydrogenation, each part byweight of the feedstock is subjected to a temperature of about 650*-900*F. in the presence of about 0.2-20 parts by weight of the partiallyhydrogenated hydrocarbon solvent, and at least one light distillatefraction and at least one heavier distillate fraction are separated fromthe hydrogenated feedstock, said heavier distillate fraction containinggas oil and dehydrogenated hydrocarbon solvent.
 14. The process of claim13 wherein the partially hydrogenated hydrocarbon solvent is partiallyhydrogenated catalytic cracker slurry oil.
 15. The process of claim 14wherein said heavier distillate fraction is catalytically cracked toproduce lower boiling products and catalytic cracker slurry oil, and thecatalytic cracker slurry oil thus produced is partially hydrogenated andused as a partially hydrogenated hydrocarbon solvent to hydrogenateadditional feedstock.
 16. A process for hydrogenating and deashing coalcomprising intimately contacting the coal in particulate form with apartially hydrogenated hydrocarbon solvent selected from the groupconsisting of partially hydrogenated catalytic cracker recycle stocks,thermally cracked stocks, and lubricating oil aromatic extracts toproduce a solution containing solubilized hydrogenated coal andsuspended insoluble material including ash, the partially hydrogenatedhydrocarbon solvent being contacted with the coal at a temperature ofabout 550*-1,000* F. and at a solvent density of at least 0.5 g./cc.,whereby hydrogen is released and the coal is solubilized therein andhydrogenated, the hydrocarbon solvent being subjected to partialhydrogenation prior to contacting it with the coal, the hydrocarbonsolvent containing a mixture of polycyclic hydrocarbons having normalboiling points of about 425*-1,000* F. and at least two condensedbenzene rings before the partial hydrogenation thereof, the partiallyhydrogenated hydrocarbon solvent containing a mixture of polycyclichydrocarbons wherein at least one of the said condensed benzene rings isretained and hydrogen is added to at least one of the said condensedbenzene rings adjacent thereto, and separating the insoluble materialfrom the hydrogenated coal solution.
 17. The process of claim 16 whereinthe partially hydrogenated hydrocarbon solvent is contacted with thecoal in the presence of elemental hydrogen.
 18. The process of claim 16wherein each part by weight of the coal is contacted with about 0.2-20parts by weight of the partially hydrogenated hydrocarbon solvent. 19.The process of claim 16 wherein the coal is contacted with the partiallyhydrogenated hydrocarbon solvent at a temperature of at least 650* F.20. The process of claim 16 wherein the hydrocarbon solvent contains amixture of polycyclic hydrocarbons having about 2-4 condensed benzenerings before partial hydrogenation, and at least one of said benzenerings is retained and 1-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation.
 21. The process of claim16 wherein the partially hydrogenated hydrocarbon solvent is partiallyhydrogenated catalytic cracker slurry oil.
 22. The process of claim 16wherein each part by weight of the coal is contacted in the presence ofelemental hydrogen at a temperature of at least 650* F. with about0.2-20 parts by weight of the partially hydrogenated hydrocarbon solventfor about 0.1-2 hours.
 23. The process of claim 22 wherein the partiallyhydrogenated hydrocarbon solvent is partially hydrogenated catalyticcracker slurry oil.
 24. The process of claim 23 wherein each part byweight of the coal is contacted with about 2-5 parts by weight of thepartially hydrogenated catalytic cracker slurry oil in the presence ofelemental hydrogen at a temperature of about 700*-850* F. and thesolvent density is at least 0.6 g./cc.
 25. The process of claim 16wherein at least one light distillate fraction is separated from thehydrogenated coal solution.
 26. The process of claim 25 wherein at leastone distillate fraction heavier than said light fraction is subsequentlyseparated from the hydrogenated coal solution, said heavier fractioncontaining heavy gas oil and dehydrogenated hydrocarbon solvent, andsaid heavy distillate fraction is catalytically cracked to produce lowerboiling products and catalytic cracker recycle stock.
 27. The process ofclaim 26 wherein the catalytic cracker recycle stock is subjected topartial hydrogenation, and the partially hydrogenated catalytic crackerrecycle stock thus prepared is used as a partially hydrogenatedhydrocarbon solvent to solubilize and hydrogenate additional coal. 28.The process of claim 16 wherein the hydrocarbon solvent contains amixture of polycyclic hydrocarbons having about 2-4 condensed benzenerings before partial hydrogenation and at least one of said benzenerings is retained and 1-3 benzene rings are hydrogenated to producenaphthenic rings during partial hydrogenation, each part by weight ofthe coal is contacted for about 0.1-2 hours with about 0.2-20 parts byweight of the partially hydrogenated hydrocarbon solvent in the presenceof elemental hydrogen and at a temperature of at least 650* F., thesolvent density is at least 0.6 g./cc. and at least one light distiLlatefraction and at least one heavier distillate fraction are separated fromthe solution of hydrogenated coal, said heavier distillate fractioncontaining gas oil and dehydrogenated hydrocarbon solvent.
 29. Theprocess of claim 28 wherein the partially hydrogenated hydrocarbonsolvent is partially hydrogenated catalytic cracker slurry oil.
 30. Theprocess of claim 29 wherein each part by weight of the coal is contactedwith about 2-5 parts by weight of the partially hydrogenated catalyticcracker slurry oil, said heavier distillate fraction is catalyticallycracked to produce lower boiling products and catalytic cracker slurryoil, and the catalytic cracker slurry oil thus produced is partiallyhydrogenated and used to solubilize and hydrogenate additional coal.